Vadanyaya is an important work by Dharmakirti on the theory of debate. The work is devoted to the rules of victory and defeat in debate. Dharmakirti has used the Nyaya account of debate, not only as a purvapaksa, a position ot be refuted, but also, at aleast partly, as a raw material for reconstruction. His criticism of Nyaya is not purely destrictuve but is has a consturctive aspect also. He gives his own classification of along with their definitions, in the first half of this work. In the second half he devotes his work to the criticism of Nyaya classification of nigrahasthanas.